Deposition mask, method of manufacturing display device using the deposition mask, and display device

ABSTRACT

Provided are a deposition mask, a method of manufacturing a display device using the deposition mask, and a display device. The deposition mask includes a main frame defining a first opening; ribs extending away from a side of the main frame, the ribs being apart from each other and defining second openings; and bridges connecting the ribs to one another across the second openings, wherein the bridges and the ribs form the same top surface, and a thickness of each of the bridges is less than a thickness of each of the ribs.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims priority to and benefits of Korean PatentApplication No. 10-2019-0153544 under 35 U.S.C. § 119, filed in theKorean Intellectual Property Office on Nov. 26, 2019, the entirecontents of which are incorporated herein by reference.

BACKGROUND 1. Technical Field

One or more embodiments relate to a deposition mask, a method ofmanufacturing a display device using the deposition mask, and a displaydevice.

2. Description of the Related Art

Recently, use of display devices has become diversified. As displaydevices have become thinner and lighter, their range of use hasgradually been extended.

As display devices may be used in various ways, display devices havebeen designed to have various shapes. Also, functions that may becombined or associated with display devices continue to increase.

It is to be understood that this background of the technology sectionis, in part, intended to provide useful background for understanding thetechnology. However, this background of the technology section may alsoinclude ideas, concepts, or recognitions that were not part of what wasknown or appreciated by those skilled in the pertinent art prior to acorresponding effective filing date of the subject matter disclosedherein.

SUMMARY

One or more embodiments may include a deposition mask, a method ofmanufacturing a display device using the deposition mask, and a displaydevice.

Additional aspects will be set forth in part in the description whichfollows and, in part, will be apparent from the description, or may belearned by practice of the presented embodiments of the disclosure.

According to one or more embodiments, a deposition mask may include amain frame defining a first opening, ribs extending away from a side ofthe main frame, the ribs being apart from each other and defining secondopenings, and bridges connecting the ribs to one another across thesecond openings, wherein the bridges and the ribs may form a same topsurface, and a thickness of each of the bridges may be less than athickness of each of the ribs.

A cross-section of each bridge may have an inverted triangle shape, thecross-section being perpendicular to a longwise direction of eachbridge.

A width of each bridge in a direction perpendicular to a lengthwisedirection of each bridge may be less than a thickness of each bridge,and a difference between the thickness of each rib and the thickness ofeach bridge may be at least about 0.5 times the width of each bridge.

A region of the main frame that neighbors the second openings may have asame shape of the bridges.

According to one or more embodiments, a display device may include asubstrate, a first display area including first pixels disposed over thesubstrate, and a second display area including second pixels disposedover the substrate and having a resolution different from a resolutionof the first display area, wherein the first pixels and the secondpixels may include a common electrode, the common electrode may includea main common electrode corresponding to the first display area, andextension portions extending from the main common electrode to thesecond display area and being apart from each other, and each of theextension portions includes a first region between the second pixels,the first region being thinner than the main common electrode.

The common electrode may further include second regions thinner than themain common electrode in connection portions of the main commonelectrode and the extension portions.

The first region may cross a corresponding extension portion among theextension portions.

A transmission area may be defined between the extension portions in thesecond display area, and the common electrode may not be disposed in thetransmission area.

A resolution of the second display area may be less than a resolution ofthe first display area.

The display device may further include a component for detecting anexternal signal, the component being disposed at a position overlappingthe second display area.

Each of the first pixels and the second pixels may include a thin filmtransistor, and an organic light-emitting diode electrically connectedto the thin film transistor, and a blocking layer may be furtherdisposed between the thin film transistor and the substrate in thesecond display area.

A first buffer layer and a second buffer layer may be further disposedon the substrate, and the blocking layer may be disposed between thefirst buffer layer and the second buffer layer.

An active layer of the thin film transistor may include a siliconmaterial, the first buffer layer may include silicon nitride, and thesecond buffer layer may include silicon oxide.

The display device may further include a planarization layer between thethin film transistor and the organic light-emitting diode, and apixel-defining layer disposed on the planarization layer and coveringedge portions of a pixel electrode of the organic light-emitting diodeto define an emission region, wherein a portion of the planarizationlayer and a portion of the pixel-defining layer corresponding to aposition overlapping the transmission area may be removed.

A number of second pixels disposed in the second display area per a unitarea may be less than a number of first pixels disposed in the firstdisplay area per the unit area.

According to one or more embodiments, a method of manufacturing adisplay device may include attaching a substrate to a deposition mask,and forming a common electrode over the substrate through the depositionmask, wherein the deposition mask may include a main frame defining afirst opening, ribs protruding away from a side of the main frame, theribs being apart from each other and defining second openings, andbridges fixing the ribs to one another by connecting the ribs across thesecond openings, each of the bridges having a thickness less than athickness of the each of the ribs, the common electrode may include amain common electrode being deposited through the first opening, andextension portions being deposited through the second openings betweenthe ribs, and the extension portions may include a first region thinnerthan the main common electrode in a position where the bridges may bedisposed.

A region of the main frame that neighbors the second openings may have asame shape of the bridges, second regions may be formed in connectionportions of the main common electrode and the extension portions, andthe second regions and the first region may have a same shape.

The ribs and the bridges may form a same top surface.

The common electrode may not be formed in a transmission area betweenthe extension portions.

A component for sensing an external signal may be further disposed at aposition overlapping at least the transmission area.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of certainembodiments of the disclosure will be more apparent from the followingdescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a schematic perspective view of an example of a display deviceaccording to an embodiment;

FIG. 2 is a schematic cross-sectional view of an example ofcross-sections of the display device taken along lines A-A′ and B-B′ ofFIG. 1 ;

FIG. 3 is a schematic perspective view for illustrating some processesof manufacturing the display device of FIG. 1 ;

FIG. 4 is a schematic plan view of a portion of a deposition mask ofFIG. 3 ;

FIG. 5 is a schematic cross-sectional view of an example of amanufacturing apparatus used during a process of manufacturing thedisplay device of FIG. 2 ;

FIG. 6 is a schematic cross-sectional view of an example of thedeposition mask taken along line II-II′ of FIG. 4 ;

FIG. 7 is a schematic plan view of the display device of FIG. 1 ;

FIG. 8 is a schematic plan view of a portion of a common electrode ofthe display device of FIG. 7 ;

FIG. 9 is a schematic cross-sectional view of an example of the displaydevice taken along line IV-IV′ of FIG. 8 ; and

FIG. 10 is a schematic cross-sectional view of an example of thedeposition mask taken along line VI-VI′ of FIG. 4 .

DETAILED DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to embodiments, examples of whichare illustrated in the accompanying drawings, wherein like referencenumerals refer to like elements throughout. In this regard, theembodiments may have different forms and should not be construed asbeing limited to the descriptions set forth herein. Accordingly, theembodiments are merely described below, by referring to the figures, toexplain aspects of the description. As used herein, the term “and/or”includes any and all combinations of one or more of the associatedlisted items. The terms “and” and “or” may be used in the conjunctive ordisjunctive sense and may be understood to be equivalent to “and/or.”Throughout the disclosure, the expression “at least one of a, b and c”indicates only a, only b, only c, both a and b, both a and c, both b andc, all of a, b, and c, or variations thereof.

It will be understood that although the terms “first,” “second,” etc.may be used herein to describe various components, these componentsshould not be limited by these terms. These components are only used todistinguish one component from another.

As used herein, the singular forms “a,” “an,” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise.

It will be further understood that the terms “comprises” and/or“comprising” used herein specify the presence of stated features orcomponents, but do not preclude the presence or addition of one or moreother features or components.

It will be understood that when a layer, region, or component isreferred to as being “formed on,” another layer, region, or component,it can be directly or indirectly formed on the other layer, region, orcomponent. For example, intervening layers, regions, or components maybe present.

Sizes of elements in the drawings may be exaggerated or reduced forconvenience of explanation. In other words, since sizes and thicknessesof components in the drawings may be arbitrarily illustrated forconvenience of explanation, the following embodiments are not limitedthereto.

When a certain embodiment may be implemented differently, a specificprocess order may be performed differently from the described order. Forexample, two consecutively described processes may be performedsubstantially at the same time or performed in an order opposite to thedescribed order.

The term overlap may include layer, stack, face or facing, extendingover, covering or partly covering or any other suitable term as would beappreciated and understood by those of ordinary skill in the art.

“About” or “approximately” as used herein is inclusive of the statedvalue and means within an acceptable range of deviation for theparticular value as determined by one of ordinary skill in the art,considering the measurement in question and the error associated withmeasurement of the particular quantity (i.e., the limitations of themeasurement system). For example, “about” may mean within one or morestandard deviations, or within ±30%, 20%, 5% of the stated value.

Unless otherwise defined, all terms used herein (including technical andscientific terms) have the same meaning as commonly understood by thoseskilled in the art to which this disclosure pertains. It will be furtherunderstood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an ideal or excessively formal sense unlessclearly defined in the specification.

FIG. 1 is a schematic perspective view of an example of a display device1 according to an embodiment.

Referring to FIG. 1 , a display area DA of the display device 1 mayinclude a first display area DA1 and a second display area DA2. Thefirst display area DA1 may be a main display area displaying a mainimage by using light emitted from first pixels Pm.

The second display area DA2 may be an area in which an input/outputcomponent 300 such as a sensor that may use a light signal or a soundsignal may be disposed (e.g., arranged) below a substrate 100. Theinput/output component 300 may emit, receive, or emit and receive, forexample, light and/or sound. A transmission area TA may be provided inthe second display area DA2 such that the input/output component 300 mayreceive an external light signal and/or sound signal, and such signalsmay be output to the outside of the display device 1 from theinput/output component. Since second pixels Pa may be disposed in thesecond display area DA2, the second display area DA2 may display animage by using light emitted from the second pixels Pa. However, sincethe transmission area TA may be disposed in the second display area DA2,the resolution of an image provided by the second display area DA2 maybe less than the resolution of an image provided by the first displayarea DA1. For example, the number of second pixels Pa disposed in thesecond display area DA2 per same unit area may be less than the numberof first pixels Pm disposed in the first display area DA1 per same unitarea.

Hereinafter, though the display device 1 according to an embodiment maybe described as an organic light-emitting display device as an example,a display device 1, a deposition mask, and a method of manufacturing adisplay device according to embodiments may be or may be applied withvarious types of display devices such as inorganic light-emittingdisplays and quantum dot light-emitting displays. Similarly, a displaydevice, a deposition mask, and a method of manufacturing a displaydevice may be applied as various technologies, including as a phone, ahead up display, a television, an artificial intelligence device, etc.

FIG. 2 is a schematic cross-sectional view of an example ofcross-sections of the display device taken along lines A-A′ and B-B′ ofFIG. 1 .

As shown in FIG. 2 , the first pixel Pm and the second pixel Pa mayinclude an organic light-emitting diode OLED having a similar structureand a thin film transistor TFT having a similar structure. A differencebetween the first pixel Pm and the second pixel Pa may be the number ofpixels per unit area in the first display area DA1 and the seconddisplay area DA2.

The display device 1 may include the substrate 100 and the input/outputcomponent 300. The substrate 100 may include the first display area DA1and the second display area DA2, and the input/output component 300 maybe disposed at a position overlapping the second display area DA2.

The input/output component 300 may include an electronic element thatmay use light or sound. For example, the input/output component 300 maybe a sensor such as an infrared sensor that emits and/or receives light,a sensor that outputs and senses light or sound to measure a distance orrecognize a fingerprint, a small lamp that outputs light, a speaker thatoutputs sound, and/or an image-pickup device. An electronic element thatuses light may use light in various wavelength bands such as visiblelight, infrared light, and ultraviolet light. The number of input/outputcomponents 300 disposed in the second display area DA2 may be providedin plural. For example, a light-emitting element and a light-receivingelement as the input/output component 300 may be provided together in asecond display area DA2. As another example, a light-emitting elementand a light-receiving element may be simultaneously provided in a singleinput/output component 300.

The substrate 100 may include glass, a polymer resin, or a combinationthereof. The polymer resin may include polyethersulfone, polyacrylate,polyetherimide, polyethylene naphthalate, polyethylene terephthalate,polyphenylene sulfide, polyarylate, polyimide, polycarbonate, celluloseacetate propionate, or a combination thereof. The substrate 100including the polymer resin may be flexible, rollable, or bendable. Thesubstrate 100 may have a multi-layered structure including a layerincluding the polymer resin, and an inorganic layer (not shown).

A buffer layer 111 may be disposed on the substrate 100. The bufferlayer 111 may reduce or block the penetration of foreign substances,moisture, or external air from below the substrate 100 and provide aflat surface on the substrate 100.

The buffer layer 111 may include an inorganic material such as an oxideor a nitride, an organic material, or an organic/inorganic compositematerial, and may include a single layer or a multi-layer including aninorganic material and an organic material. For example, the bufferlayer 111 may have a structure in which a first buffer layer 111 a and asecond buffer layer 111 b may be stacked. The first buffer layer 111 aand the second buffer layer 111 b may include different materials. Forexample, the first buffer layer 111 a may include silicon nitride, forexample, SiN_(x). The second buffer layer 111 b may include siliconoxide, for example, SiO_(x).

In the case where the first buffer layer 111 a includes silicon nitride,hydrogen may be included in forming the silicon nitride. Through thistechnique, the carrier mobility of an active layer 1130 formed on thebuffer layer 111 may be improved and the electric characteristic of athin film transistor TFT may be improved. The active layer 1130 mayinclude a silicon material. An interface bonding characteristic betweenthe active layer 1130 including silicon and the second buffer layer 111b including silicon oxide may be improved and thus the electriccharacteristic of the thin film transistor TFT may be improved.

The thin film transistor TFT may be disposed on the buffer layer 111,the thin film transistor TFT including the active layer 1130, a gateelectrode G, a source electrode S, and a drain electrode D. Hereinafter,though a top gate-type thin film transistor TFT in which the gateelectrode G disposed over the active layer 1130 may be described, thethin film transistor TFT may be a bottom gate-type thin film transistorin which the gate electrode G may be disposed below the active layer1130.

The active layer 1130 on the buffer layer 111 may include, for example,polycrystalline silicon. The active layer 1130 may include a channelregion, a source region, and a drain region, the channel regionoverlapping the gate electrode G. The source region and the drain regionmay be disposed on two opposite sides of the channel region and dopedwith impurities having a higher concentration than that of the channelregion. Here, the impurities may include N-type impurities or P-typeimpurities. In another embodiment, the active layer 1130 may includeamorphous silicon or an organic semiconductor material. In anotherembodiment, the active layer 1130 may include an oxide semiconductor.

The gate electrode G may be disposed over the active layer 1130 with afirst gate insulating layer 112 therebetween. The gate electrode G mayinclude at least one of molybdenum (Mo), aluminum (Al), copper (Cu), andtitanium (Ti), and may include a single layer or a multi-layer.

The first gate insulating layer 112 may include at least one of siliconoxide (SiO₂), silicon nitride (SiN_(x)), silicon oxynitride (SiON),aluminum oxide (Al₂O₃), titanium oxide (TiO₂), tantalum oxide (Ta₂O₅),and hafnium oxide (HfO₂), and zinc oxide (ZnO₂).

A second gate insulating layer 113 may cover the gate electrode G. Thesecond gate insulating layer 113 may include at least one of siliconoxide (SiO₂), silicon nitride (SiN_(x)), silicon oxynitride (SiON),aluminum oxide (Al₂O₃), titanium oxide (TiO₂), tantalum oxide (Ta₂O₅),and hafnium oxide (HfO₂), and zinc oxide (ZnO₂).

The source electrode S and the drain electrode D may be disposed on aninterlayer insulating layer 115. The source electrode S and the drainelectrode D may include a conductive material including molybdenum (Mo),aluminum (Al), copper (Cu), titanium (Ti), or a combination thereof, andmay include a single layer or a multi-layer including the abovematerials.

A planarization layer 117 may be disposed on the source electrode S andthe drain electrode D. An organic light-emitting diode OLED may bedisposed on the planarization layer 117. The organic light-emittingdiode OLED may be electrically connected to the thin film transistorTFT. For example, the organic light-emitting diode OLED may beelectrically connected to the drain electrode D.

The planarization layer 117 may have a flat top surface such that apixel electrode 210 may be formed flat. The planarization layer 117 mayinclude a single layer or a multi-layer including an organic material.The planarization layer 117 may include a general-purpose polymer suchas benzocyclobutene (BCB), polyimide, hexamethyldisiloxane (HMDSO),polymethylmethacrylate (PMMA) or polystyrene (PS), polymer derivativeshaving a phenol-based group, an acryl-based polymer, an imide-basedpolymer, an aryl ether-based polymer, an amide-based polymer, afluorine-based polymer, a p-xylene-based polymer, a vinyl alcohol-basedpolymer, or a blend thereof. The planarization layer 117 may include aninorganic material. The planarization layer 117 may include at least oneof silicon oxide (SiO₂), silicon nitride (SiN_(x)), silicon oxynitride(SiON), aluminum oxide (Al₂O₃), titanium oxide (TiO₂), tantalum oxide(Ta₂O₅), and hafnium oxide (HfO₂), and zinc oxide (ZnO₂). In the casewhere the planarization layer 117 includes an inorganic material,chemical mechanical polishing may be performed depending on the case.The planarization layer 117 may include both an organic material and aninorganic material.

The pixel electrode 210 may include a (semi)-transparent electrode or areflective electrode. In an embodiment, the pixel electrode 210 mayinclude a reflective layer and a transparent or (semi)-transparentelectrode layer on the reflective layer, the reflective layer includingsilver (Ag), magnesium (Mg), aluminum (Al), platinum (Pt), palladium(Pd), gold (Au), nickel (Ni), neodymium (Nd), iridium (Ir), chrome (Cr),or a compound thereof. The transparent or (semi)-transparent electrodelayer may include at least one of indium tin oxide (ITO), zinc oxide(IZO), zinc oxide (ZnO), indium oxide (In₂O₃), indium gallium oxide(IGO), and aluminum zinc oxide (AZO). In an embodiment, the pixelelectrode 210 may have a stacked structure of ITO/Ag/ITO.

A pixel-defining layer 119 may be disposed on the planarization layer117. The pixel-defining layer 119 may define an emission region byincluding an opening corresponding to a pixel, that is, an openingexposing at least a central portion of the pixel electrode 210. Thepixel-defining layer 119 may prevent an arc, etc. from occurring betweenedges of the pixel electrode 210 and the common electrode 230 byincreasing a distance between the edges of the pixel electrode 210 andthe common electrode 230. The pixel-defining layer 119 may include, forexample, an organic material such as polyimide or HMDSO.

An intermediate layer 220 may include a low molecular weight material ora polymer material. In the case where the intermediate layer 220includes a low molecular weight material, the intermediate layer 220 mayhave a structure in which an HIL, an HTL, an emission layer (EML), anETL, an EIL, etc. may be stacked in a single or a compositeconfiguration. The intermediate layer 220 may include various organicmaterials such as copper phthalocyanine (CuPc), N, N′-Di(naphthalene-1-yl)-N, N′-diphenyl-benzidine (NPB),tris-8-hydroxyquinoline aluminum (Alq3), or a combination thereof. Theselayers may be formed by vacuum deposition.

In the case where the intermediate layer 220 includes a polymermaterial, the intermediate layer 220 may have a structure including anHTL and an EML. The HTL may include poly-3, 4-ethylene dioxy thiophene(PEDOT), and the EML may include a polymer material such as apolyphenylene vinylene (PPV)-based material or a polyfluorene-basedmaterial. The structure of the intermediate layer 220 is not limited tothe above description and may have various structures. For example, atleast one of layers constituting the intermediate layer 220 may beformed as one body over the pixel electrodes 210. As another example,the intermediate layer 220 may include a layer patterned to correspondto each of the pixel electrodes 210.

The common electrode 230 may include a transparent electrode or areflective electrode. In an embodiment, the common electrode 230 mayinclude a transparent or semi-transparent electrode and may include ametal thin layer having a small work function and including at least oneof lithium (Li), calcium (Ca), lithium fluoride (LiF)/Ca, LiF/aluminum(Al), Al, silver (Ag), magnesium (Mg), and a compound thereof. Thecommon electrode 230 may be disposed over the first display area DA1 andthe second display area DA2 and disposed on the intermediate layer 220and the pixel-defining layer 119.

The transmission area TA of the second display area DA2 may be an areathrough which a light signal and/or a sound signal emitted from theinput/output component 300 passes. For precise signal transfer, thecommon electrode 230 may not be formed in the transmission area TA.According to an experiment, a case where the common electrode 230 maynot be formed in the transmission area TA shows about 1.5 times highertransmittance than a case where the common electrode 230 may be formedin the transmission area TA. A process of manufacturing the commonelectrode 230 having this characteristic structure is described below.Also, to improve a transmittance of the transmission area TA, theplanarization layer 117 and the pixel-defining layer 119 may be removedfrom the transmission area TA.

A blocking layer BSM may be disposed between the substrate 100 and thethin film transistor TFT in a position overlapping the second pixel Pain the second display area DA2. The blocking layer BSM blocks the thinfilm transistor TFT such that the thin film transistor TFT may not beinfluenced by a light signal or a sound signal from the input/outputcomponent 300 adjacent thereto. For example, the blocking layer BSM maybe disposed between the first buffer layer 111 a and the second bufferlayer 111 b.

Though not shown, a thin-film encapsulation layer may be formed on thecommon electrode 230, the thin-film encapsulation layer including atleast one inorganic encapsulation layer and at least one organicencapsulation layer that may be stacked. The inorganic encapsulationlayer may include at least one inorganic insulating material amongaluminum oxide, titanium oxide, tantalum oxide, hafnium oxide, zincoxide, silicon oxide, silicon nitride, and silicon oxynitride. Theorganic encapsulation layer may include polyethylene terephthalate,polyethylene naphthalate, polycarbonate, polyimide, polyethylenesulfonate, polyoxymethylene, polyacrylate, HMDSO, an acryl-based resin(e.g. polymethylmethacrylate, polyacrylic acid, etc.), or a combinationthereof.

FIG. 3 is a schematic perspective view of some processes ofmanufacturing the display device of FIG. 1 . FIG. 4 is a schematic planview of a portion of a deposition mask of FIG. 3 . FIG. 5 is a schematiccross-sectional view of an example of a manufacturing apparatus usedduring a process of manufacturing the display device of FIG. 2 . FIG. 6is a schematic cross-sectional view of an example of the deposition masktaken along line II-II′ of FIG. 4 .

FIG. 3 shows a method of forming the common electrode 230 (see FIG. 7 )over the substrate 100. Specifically, a deposition mask 10 may beclosely attached to the substrate 100, and a material that forms thecommon electrode 230 (see FIG. 7 ) may be deposited over the substrate100 through the deposition mask 10. The common electrode 230 (see FIG. 7) may be formed over the first display area DA1 and the second displayarea DA2 by one-time deposition process. For this purpose, thedeposition mask 10 may include a first opening 12 and ribs 13, the firstopening 12 corresponding to the first display area DA1.

The first opening 12 may be defined by a main frame 11 of the depositionmask 10. The ribs 13 may protrude from a side of the main frame towardthe outside in a plan view to correspond to the second display area DA2.For example, the ribs 13 may protrude from the side of the main frame 11away from the main frame 11.

The ribs 13 may be apart from each other, and as shown in FIG. 4 ,second openings 15 may be defined between the ribs 13. Since the ribs 13may be disposed to correspond to the transmission area TA (see FIG. 6 ),consequently, the common electrode 230 (see FIG. 7 ) may not bedeposited in the transmission area TA (see FIG. 6 ).

In contrast, the second openings 15 may be formed in positions tooverlap the second pixels Pa. Though this configuration, the commonelectrode 230 (see FIG. 7 ) may be deposited on positions correspondingto the second pixels Pa. A width of the second opening 15 may be greaterthan a width of the second pixels Pa. As a result, the common electrode230 (see FIG. 7 ) deposited through the second openings 15 may cover thesecond pixels Pa. Here, the width of the second pixels Pa may mean awidth of a width of the pixel-defining layer 119 (see FIG. 2 ) definingthe emission region. Therefore, even though a minute alignment errorbetween the deposition mask 10 and the substrate 100 may occur during aprocess of forming the common electrode 230 (see FIG. 7 ), theoccurrence of a formation defect of the common electrode 230 (see FIG. 7) may be prevented.

The ribs 13 may be connected to each other by bridges 14. For example,the bridge 14 may cross the second opening 15 and be disposed betweenforming regions of the second pixels Pa. Here, in case that the bridge14 may be referred to as crossing the second opening 15, it may not onlycross the second opening 15 at a shortest distance but also mayobliquely cross the second opening 15 with a straight shape depending ona position of the second pixels Pa as shown in FIG. 4 . The bridge 14may allow the common electrode 230 (see FIG. 7 ) to be formed at anaccurate position in the second display area DA2 by fixing the positionsof the ribs 13 extended from the main frame 11.

The forming of the common electrode 230 (see FIG. 7 ) by using thedeposition mask 10 may be performed by using a manufacturing apparatus400 shown in FIG. 5 . The manufacturing apparatus 400 may include achamber 410, a mask assembly 420, a first supporter 430, a secondsupporter 440, a deposition source 450, a magnetic force generator 460,a vision part 470, and a pressure adjuster 480.

The chamber 410 may include a space therein, and a portion of thechamber 410 may be open. A gate valve 411 may be disposed in an openportion of the chamber 410 such that the gate valve 411 may beopened/closed. The pressure adjuster 480 may be connected to the chamber410 to adjust the pressure of the inside of the chamber 410. Thepressure adjuster 480 may include a connection pipe 481 and a pump 482,the connection pipe 481 being connected to the chamber 410, and the pump482 being disposed at the connection pipe 481.

The mask assembly 420 may include a mask sheet 422 and a mask frame 421coupled to the mask sheet 422. The mask sheet 422 may include thedeposition mask 10 described above. For example, the mask sheet 422 mayinclude multiple deposition masks 10. The mask sheet 422 may be fixed tothe mask frame 421 with tensile force applied thereto.

The substrate 100 may be safely seated on the first supporter 430. Thefirst supporter 430 may adjust the position of the substrate 100. Forexample, the first supporter 430 may include a UVW stage. The maskassembly 420 may be safely seated on the second supporter 440. Similarlyto the first supporter 430, the second supporter 440 may adjust theposition of the mask assembly 420.

The deposition source 450 may receive a deposition material andevaporate or sublimate the deposition material to supply the depositionmaterial to the chamber 410. The deposition source 450 may include aheater therein and melt or sublimate the deposition material by heatingthe deposition material inside the deposition source 450 through anoperation of the heater.

The vision part 470 may be disposed on the chamber 410 and mayphotograph the positions of the mask assembly 420 and the substrate 100.The vision part 470 may photograph an alignment mark of at least one ofthe mask assembly 420 and the substrate 100.

The magnetic force generator 460 may be disposed in the chamber 410 andmay closely attach the substrate 100 to the mask assembly 420. Themagnetic force generator 460 may include an electromagnet or a permanentmagnet generating magnetic force. As described above, since thedeposition mask 10 may include the bridge 14 that may fix the positionsof the ribs 13 extended from the main frame 11, the deposition mask 10may prevent the positions of the ribs 13 from being twisted while thesubstrate 100 may be closely attached to the mask assembly 420. As aresult, the common electrode 230 (see FIG. 7 ) may be deposited at anaccurate position in the second display area DA2.

The common electrode 230 (see FIG. 7 ) in the second display area DA2may be deposited through the second openings 15 between the ribs 13. Thebridge 14 may be disposed to cross the second openings 15. However, itmay be required that the common electrode 230 (see FIG. 7 ) depositedthrough the second openings 15 may not be disconnected by the bridge 14.For this purpose, as shown in FIG. 6 , the bridge 14 and the rib 13 mayform the same top surface, and a thickness of the bridge 14 may be lessthan a thickness of the rib 13. For example, since a bottom surface ofthe bridge 14 may be apart from a deposition surface on which the commonelectrode 230 may be deposited, the common electrode 230 may bedeposited also below the bridge 14, and the common electrode 230 (seeFIG. 7 ) may be continuously formed in the second display area DA2without being disconnected by the bridge 14.

Since the ribs 13 have a protruding shape from the main frame 11 of thedeposition mask 10, the common electrode 230 (see FIG. 7 ) should beprevented from being disconnected by the main frame 11 in the firstdisplay area DA1 and the second display area DA2. For this purpose, aregion P of the main frame 11 that neighbors the second opening 15 mayhave the same shape as that of the bridge 14. For example, a portion ofthe main frame 11 corresponding to the region P may have a thicknessless than that of the surroundings, and a cross-section of thedeposition mask 10 taken along line II-II′ of FIG. 4 and a cross-sectionof the deposition mask 10 taken along line III-Ill′ of FIG. 4 may havethe same shape as shown in FIG. 6 . As a result, in case of depositingthe common electrode 230 (see FIG. 7 ) by using the deposition mask 10,the common electrode 230 (see FIG. 7 ) may be prevented from beingseparated in the first display area DA1 and the second display area DA2.

FIG. 7 is a schematic plan view of the display device of FIG. 1 . FIG. 8is a schematic plan view of a portion of the common electrode of thedisplay device of FIG. 7 . FIG. 9 is a schematic cross-sectional view ofan example of the display device taken along line IV-IV′ of FIG. 8 .

First, as shown in FIG. 7 , the display area DA may include the firstdisplay area DA1 and the second display area DA2 respectively havingdifferent resolutions. The common electrode 230 may include a maincommon electrode 230 a and extension portions 230 b, the main commonelectrode 230 a being disposed in the first display area DA1, and theextension portions 230 b being disposed in the second display area DA2.

The common electrode 230 may be formed through one-time depositionprocess by using the deposition mask 10 (see FIG. 3 ) described above.Through this, the main common electrode 230 a and the extension portions230 b may be formed as one body. Therefore, the first pixels Pm and thesecond pixels Pa may include the common electrode 230 provided as onebody.

The first pixels Pm may be densely disposed in the first display areaDA1, and the main common electrode 230 a may be formed as one body tocorrespond to the first pixels Pm.

Since the second pixels Pa may be less densely disposed in the seconddisplay area DA2 than the first pixels Pm, the resolution of the seconddisplay area DA2 may be less than the resolution of the first displayarea DA1. The extension portions 230 b may protrude from the main commonelectrode 230 a and respectively correspond to the second pixels Pa.

Although it is shown in FIG. 7 that the extension portions 230 b mayhave a zigzag shape, the shape of the extension portions 230 b may bevariously changed depending on the arrangement of the second pixels Pa.For example, the extension portions 230 b may be formed long in astraight line shape or obliquely formed, depending on the arrangement ofthe second pixels Pa. The extension portions 230 b may be apart fromeach other in a direction perpendicular to the extension direction toform the transmission area TA.

The extension portions 230 b may respectively cover the second pixelsPa, and a width of an extension portion 230 b may be greater than awidth of a second pixel Pa. Here, the width of the second pixels Pa maymean a width of the opening of the pixel-defining layer 119 (see FIG. 2) defining the emission region. The extension portion 230 b may includea first region G between the second pixels Pa, the first region G beingthinner than a thickness of the main common electrode 230 a. The firstregion G may have a concave shape having a top surface that may be lessthan a top surface of the surroundings. The first region G may be formedat a position at which the bridge 14 (see FIG. 4 ) described above maybe disposed and may have the same pattern as that of the bridge 14 (seeFIG. 4 ). For example, the first region G may cross the extensionportion 230 b.

As described above, since the region P of the main frame that neighborsthe second opening 15 (see FIG. 4 ) may have the same shape as that ofthe bridge 14 (see FIG. 4 ), the common electrode 230 may furtherinclude a second region Q having a height less than that of the commonelectrode 230 adjacent thereto, the second region Q being at aconnection portion of the main common electrode 230 a and the extensionportion 230 b. For example, cross-sections of the display device takenalong line IV-IV and line V-V of FIG. 8 may have the same shape as shownin FIG. 9 .

FIG. 10 is a schematic cross-sectional view of an example of thedeposition mask taken along line VI-VI′ of FIG. 4 .

FIG. 10 shows a cross-sectional shape perpendicular to a lengthwisedirection of the bridge 14. As described above, since the bottom surfaceof the bridge 14 may be apart from the deposition surface, the commonelectrode 230 (see FIG. 7 ) may be deposited below the bridge 14. Incase of depositing the common electrode 230 (see FIG. 7 ), thedeposition material may be obliquely incident. To improve a depositionefficiency of a portion below the bridge 14, a shape of a verticalcross-section of the bridge 14 may be an inverted triangle. However, thedisclosure is not limited thereto and the bridge 14 may have variousshapes.

To improve the efficiency of depositing the common electrode 230 (seeFIG. 2 ) below the bridge 14, a thickness T2 of the bridge 14 may begreater than a width W of the bridge 14, and a difference between athickness T1 of the rib 13 and the thickness T2 of the bridge 14 may beat least about 0.5 times the width W of the bridge 14.

According to embodiments, since an image may be displayed even in anarea in which an input/output component may be disposed, a displaydevice in which a display area may be extended may be implemented. Thecommon electrode may be formed in an entire region including a maindisplay area and an area in which an input/output component may bedisposed by one-time deposition process.

It should be understood that embodiments described herein should beconsidered in a descriptive sense only and not for purposes oflimitation. Descriptions of features or aspects within each embodimentshould typically be considered as available for other similar featuresor aspects in other embodiments. While one or more embodiments have beendescribed with reference to the figures, it will be understood by thoseof ordinary skill in the art that various changes in form and detailsmay be made therein without departing from the spirit and scope asdefined by the following claims, including their equivalents.

What is claimed is:
 1. A display device comprising: a substrate; a first display area including first pixels disposed over the substrate; and a second display area including second pixels disposed over the substrate and having a resolution different from a resolution of the first display area, wherein the first pixels and the second pixels include a common electrode, the common electrode includes: a main common electrode corresponding to the first display area; and extension portions extending from the main common electrode to the second display area and being apart from one another, and each of the extension portions includes a first region between the second pixels, the first region being thinner than the main common electrode.
 2. The display device of claim 1, wherein the common electrode further includes second regions thinner than the main common electrode in connection portions of the main common electrode and the extension portions.
 3. The display device of claim 1, wherein the first region crosses a corresponding extension portion among the extension portions.
 4. The display device of claim 1, wherein a transmission area is defined between the extension portions in the second display area, and the common electrode is not disposed in the transmission area.
 5. The display device of claim 4, wherein a resolution of the second display area is less than a resolution of the first display area.
 6. The display device of claim 4, further comprising a component for detecting an external signal, the component being disposed at a position overlapping the second display area.
 7. The display device of claim 6, wherein each of the first pixels and the second pixels includes: a thin film transistor; and an organic light-emitting diode electrically connected to the thin film transistor, and a blocking layer is further disposed between the thin film transistor and the substrate in the second display area.
 8. The display device of claim 7, further comprising a first buffer layer and a second buffer layer disposed on the substrate, wherein the blocking layer is disposed between the first buffer layer and the second buffer layer.
 9. The display device of claim 8, wherein an active layer of the thin film transistor includes a silicon material, the first buffer layer includes silicon nitride, and the second buffer layer includes silicon oxide.
 10. The display device of claim 7, further comprising: a planarization layer between the thin film transistor and the organic light-emitting diode; and a pixel-defining layer disposed on the planarization layer and covering edge portions of a pixel electrode of the organic light-emitting diode to define an emission region, wherein a portion of the planarization layer and a portion of the pixel-defining layer corresponding to a position overlapping the transmission area are removed.
 11. The display device of claim 1, wherein a number of second pixels disposed in the second display area per a unit area is less than a number of first pixels disposed in the first display area per the unit area. 